Telephone subset



1940- E. s. M LARN TELEPHONE SUBSET Filed Dec. 24, 1937 6 Sheets-Sheet l INVENTOR [FA/[$75 MCLflR/V BY 5' ATTORNEY Dec. 31, 1940. E. s. M LARN TELEPHONE SUBSET Fi led Dec.

24, 1937 6 Sheets-Sheet 2 Ef E Dec. 31, 1940. E. s. MCLARN TELEPHONE SUBSET Filed Dec. 24, 1937 6 Sheets-Sheet 3 ATTOR N EY 1940- E. s. M LARN I ,226,734

TELEPHONE SUBSET Filed Dec. 24, 1937 I 6 Sheets-Sheet 4 .H J IM W E: IN?

BY ATTORNEY E. s. M =L-ARN 2,226,734

TELEPHONE SUBSE';

Filed Dec. 24, 1937 6 Sheets-Sheet 5 Dec. 31, 1940.

:wm 96m 1 ATTORNEY Dec. 31, 1940. E. s. M LARN TELEPHONE SUBSET e Sheets- Sheet 6 Filed Dec 24, 1937 LL tw/vzsramc 40/? ATTORNEY Patented Dec. 31, 19 40 UNITED STATES 2,226,734 TELEPHONE SUBSET Ernest S. McLarn, Manhasset, N. Y., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application December 24, 1937, Serial No. 181,493 g Claims.

This invention relates to telephone subsets and pertains more particularly to hand set mountings or desk sets wherein the various components ordinarily put in the bell box are instead in- 5 cluded in the hand set mounting .or desk set itself.

It is an object of my invention to provide an improved form of telephone hand set mounting in size and durable in operation.

A further object of my invention is to provide a telephone hand set mounting or desk set which may be quickly, easily and cheaply repaired when necessary.

'In accordance with my invention I provide a hand set mounting or desk set, hereinafter for simplicity referred to as a-desk set, wherein the ringer unit, condenser and inductance coil are each individually potted so as to be. protected from moisture and all of these elements are positioned within the desk setand connected together in the necessary manner without the aid of connecting cables or exposed wires. This is done by providing a molded terminal block carrying a plurality of terminal connections and imbedded conductors, by means or which the several component parts of the desk set may be interconnected by use of binding screws. 1

Preferably, this molded terminal block also carries the spring nest of the plunger switch whereby exposed circuit connections are still further reduced.

The above mentioned and further objects and advantages of my invention and the manner of attaining them will be more fully explained in the following description and accompanying drawings.

Fig. 1 is a side elevation view partly in section taken along section line I--I of Fig. 2, of a telephone desk set constructed in accordance with my invention. t

Fig. 2 is a horizontal sectional view taken along section line 2-2 of Fig. 1.

Fig. 3 is'a fragmentary sectional view showing the cradle assembly of Fig. 1 rotated 180 so that the desk set may be attached to the side of a desk or to a wall.

Figs. 4, 5 and 6 are, respectively, plan view,

front view and end view of the terminal block forming part of the assembly shown inFig. 1.

Fig. 7 is a sectional view taken along. section line I-| of Fig. 4.

Fig. 8 is a sectional view taken along section line 88 of F18. l.

or desk set which is simple in construction, small Fig. 9 is a sectional view taken along sectional line 99 of Fig. 4. i I

Fig. 10 is a view similar to Fig. 9 but showing in addition the clamping means for making the 5 necessary connections.

Fig. 11 is a view similar to the left hand part of Fig. 7 but showing in addition the clamping means for making the necessary connections.

Fig. 12 is a plan view of a metal punching used in making the connections inserted in the terminal block.

Fig. 13 shows in plan view and partly in section an alternative method of making the terminal block. 15

Fig. 14 shows a sectional view taken along the line H-H of Fig- 13.

Fig. 15 shows the circuit connections for the desk set.

Referring more particularly to Fig. 1, reference numeral i indicates a base plate having attached thereto, e. g. by spot welding, a bracket 2. This bracket carries at its upper end a closure collar 3, which is spot welded or otherwise fastened to the upper end of the bracket. A cradle assembly 25 4, is positioned above and supported by the bracket, this assembly comprising a molded or cast cradle 5 having a metal insert 8 in the form of a ring or sleeve which projects through a corresponding opening I in the closure collar 3 and 30 bracket 2 and serves as a pivot point or bearing around which the cradle assembly may be rotated through an angle of whereby the cradle assembly may be positioned either at right angles I to the base plate, as shown in Fig. 1, or in a direction substantially parallel with the base plate, as shown in fragmentaryview 3. The first position permits the use of the device as a desk set. while the latter position permits the use of the device as a wall set attached either to the wall of a room or to the side of a desk. In both positions the hand set which rests on the cradle is readily accessible and the position of the cradle is such as firmly to hold the hand set. i

The ring or sleeve 6 has adjacent one end thereof a circulardepression 8 in which is resiliently positioned a holding ring or wire 9 which acts to prevent the removal of the cradleassembly from the bracket 2 by which it is supported. Reference numeral l0 indicates a detent 50 or spring pressed plunger which is adapted to fit in one of two depressions H and in the face of the cradle 5 which lies adjacent to the closure ring 3. In the position of the parts sh n in Fig. 1, the detent llipresses into the de angles to the base plate. on the other hand,

when the cradle is rotated to as shown in Fig. 3, the detent then engages with depression II. The detent pin is pressed towards the cradle I by means of a leaf spring II fixed to the bracket 2.

The cradle I has a countersunk opening l4 therein within which is positioned rod ll of the plunger switch indicated generally by reference numeral II. This rod passes through a hard rubber bushing I1 and then through a roller bearing guide II, the latter having two rollers I! and 20 which serve to take up side thrust of the rod I. This side thrust results from the contacting of conical head 2i fixed to the rod with actuating contact arm 22 of spring nest 23. This cont-act arm has a roller 24 journaled thereto, which makes the actual contact with the conical head 2i. Twenty-five (25) indicates a spring pressing against a washer 28 which is in turn held in place by presser bar 21 to which the end of rod I5 is screw threaded at 28. A cover 29 fits over the cradle assembly and is fastened to the base at one end by means of a projection 20 on the inside of the cover engaging with a clip II attached to the base plate, and at the other end by a screw 32 which engages with a hole in the bracket 2. The closure collar 2 fits within a corresponding opening in-the cover 29 and since this ring is preferably formed of resilient and relatively thin metal it conform to the shape of the opening and forms a complete dust-tight closure. This. function is aided by the somewhat flaring shape of the closure collar which insures a wedging action when the cover 29 is placed in position and secured to the base plate. The cover, as shown in Fig. 1, has an instrument blank 32 attached thereto which may be removed for the insertion of a dial.

Attached to the base plate I are terminal block 34 and active circuit component units including induction coil 25, ringer 36 and condenser 21. The terminal block 34 is preferably of molded material having imbedded therein the necessary connections which terminate in a series of terminals ll, 39, 40, 4|, 42, 43, 44, 45, 48, as shown, for example in Fig. 2. This terminal block is held in position on the base plate by means of screws 41, 48 and 49. The induction coil, ringer and condenser, each have terminals to engage with those of the terminal block just mentioned and are attached thereto by binding screws. The end of each of these units opposite that from which the connections project, is attached to the base plate by means of a screw and clamp as shown at 50, BI and 52. Each of the several units, Just mentioned is preferably positioned within a suitable open sided housing or casing and protected by high melting point potting compound. The housings are desirably of Bakelite or other molded insulating material but alternatively may be of metal, the proper insulating bushings being supplied for the terminals.

Referring to the induction coil and the condenser, the open sides of their casings are preferably placed next to the base plate while the ringer housing is positioned with its open side up, allowing an adjustment of the biasing spring 53 and other parts of the clapper rod and armature assembly 54 may be made.

As shown in Fig. 2, the case 55 of the ringer 36 has a partition 58 which separates the magnet coils 51 from the clapper rod and armature assembly 54, this partition serving to confine the potting compound to the magnet coils 5-! lmving the clapper rod assembly 54 free from the potting compound.

Figs. 4 to 11, inclusive, show the details of construction of the terminal block 34 and make plain the manner of construction thereof.

It will be clear from these drawings that the several terminal connections ll to 48, inclusive. are molded into the terminal block and that all of these terminals, with the exception of 43, have connections to various other parts likewise molded into the block 24.

The individual springs of spring nest 23 are likewise molded into the block 34 as shown, perhaps most clearly, in Fig. 7. These springs re welded, soldered or otherwise suitably connected with conductors leading to the proper terminals of the terminal block, as shown in Fig. 8.

Reference numerals 58 and 59 indicate connecting prongs or teeth which are intended to pierce the insulation of a conductor or cord which is to be connected to the terminal block. The cord is arranged to be held in position by means of a clamp 60 and screws 8i which draw the clamp towards the associated prongs and at the same time form a circuit connection between conductor rings 12 and 13. This structure is shown in Figs. 10 and 11. A connector of this type is disclosed in my copending application Serial No. 146,539, filed June 5, 1937.

In Fig. 10 the binding screw arrangement of the terminal connections is shown. This consists of a binding screw 62 which passes through an opening in the terminal connection and engages with a perforated strip of metal having two tongues therein and sold for example under the trade name Speednut. This perforated strip of metal 63 is U-shaped and is in effect folded around the end of the terminal connection, as shown in Fig. 10. Each of the terminal connections has a projecting finger 64 which extends through a corresponding opening in the loop of the elements 63. This finger serves to retain the loop of metal in position and prevents turning thereof during the tightening of the screw.

As shown in Figs. 4, 7 and 8, a threaded stud or nut I! is welded, soldered or otherwise fastened to one of the connecting strips 66 of the terminal block and this stud extends above the surface of the block so that a binding screw connection may be made thereto. A connecting link 66, which appears in Figs. 1 and 2, is provided so that a connection can be made either from 65 to 43 or from 42 to 45, depending on whether the desk set is to be used with a loop ringing or grounded ringing circuit. An alternative method of effecting a connection between the conductor 86 and one of the terminals 43 and 45 is shown in connection with Figs. 13 and 14, wherein the switch spring connected to conductor 66 by welding, soldering or other suitable means, is bent at right angles as shown at 81, so as to pass below the ends of the other springs forming the spring nest 23 and out of the block to form an external terminal 68 similar to the terminal connections 38 to 48, inclusive. From this terminal a connector link 69 may be extended to the connector 43.

this case the boss III for receiving the holding screw 49 is displaced slightly to the left out of line with the spring nest so that the terminal connector 81 will be out of the path of the holding screw.

Fig. '12 shows a layout of the several conductors and terminal connections which are utilized 40 x more that the hand set cord and line cord have in the terminal block a. A singlestrip of metal may be punched in a single operation to form the several connections shown in Fig. 12, all of these connections except that forming conductor 66 being held together by a single connector strip 1|. After the punching operationis completed the prongs N and are bent down at right angles. The conductor rings I2 and I3 and prongs are twisted into alignment so as to occupy the position shown in Figs. 7 and 8, then the entire group of conductors withtheir integrally formed terminal connectors are placed in a mold and insulating material such as Bakelite, hard rubber or the like, is molded around them to form the finished product. After the molding operation is completed the holding strip II is sheared off leaving the terminals all in their proper positions ready for electrical connection to form the desired circuit. The stud 65 if used is previously welded to an enlarged portion ll of the conduc tor i6 and likewise the springs of the spring nest 23 are welded to the ends 15 of the associated conductors so that when the molding operation is completed the stud i5 is imbedded in the insulation with Just its surface showing-and likewise the ends of the spring nest are imbedded in the insulation so that they will be held in, the proper relative position after the insulation solidifies.

It is possible to cut out all of the parts forming the several conductors in one punching operation because of the arrangement of the apparatus elements which have been selected. By this arrangement of elements which is shown, for example, in Fig. 2 and has been described hereinabove, all cross-over connections which would prevent the punching of all of the conductors in one operation have been avoided and this results from the fact that the condenser and induction coil have been placed on each side of the ringer,

as already explained hereinbefore, and furtherbeen positioned as shown, the hand set cord being adjacent to the induction coil and the line adjacent to the condenser. Since cross-over connections have been avoided, the assembling and molding operation, as well as the punching operation for forming the conductors, is relatively simple.

Fig. 15 shows a circuit diagram of the desk set, the cases of the several component parts being shown in dotted lines inthe interests of clarity. This circuit diagram illustrates the con-. nections using a hand set with the calling dial attached thereto, as shown for example in my copending application Ser. No. 146,539, filed June 5, 1937.

In this drawing reference numerals 16, 11 and 18, indicate respectively, the receiver, transmitter and calling dial, while I9 is the usual terminal block. Eighty (80) is the line cord and 8| the hand set cord. Where the instrument is to be used for the first party of a selective two-party line cooperating with the usual circuits of the rominal 43 to 45, while for the second party there should be in addition a strap connection between terminals N and 42. Reference numerals 82, 83,

indicate louvers or openings in the cover- 29 through which the sound of the ringer bells may easily pass.

From the foregoing description it will be seen that I have provided a very simple form of desk set wherein each of the individual parts is separately potted in such manner as to form a -mois-' ture and corrosion proof entity, which can read- 1 be inserted into the desk set and removed therefrom as a unit. Furthermore it will be understood that the several units can be associated with the terminal block which carries all of the necessary connections in a very simple, easy and reliable manner, merely by the aid of a screw driver. The terminal block itself, as already stated, carries all of the necessary connections and is firmly fixed to the base plate. The induction coil, ringer and condenser are held firmly in position by screw terminals attaching the same to the terminal block at one end and by means of separate clamping elements at the other end. Therefore, in servicing a desk set of this character in the field, it is necessary merely to locate the defective element or unit, then to remove this by loosening the several screws involved, so that a new unit may be quickly inserted by the use of a screw driver solely and without the necessity for soldering connections.

' Since the cable and flexible wire connectors ordinarily utilized in conjunction with solderedjoints to form the circuit connections of a desk set according to the prior art are eliminated, not only is it assured that circuit difficulties arising from breaking of the several strands of the cable or failure of the soldered Joints are obviated, but

also the changing of the several units in the des set is greatly simplified. I I

Furthermore, since the spring nest 23 is molded into position in the terminal block 34, no looseness of the springnest in operation can result. The mounting of the individual units on the base plate andthe provision of the bracket 2 for holding the cradle assembly 4, also has the advantage of necessitating only a very simple and cheap cover or housing 29 which is inexpensive to form, for example by a molding operation,

since there are no bosses, projections or inserts which would add to the expense of manufacture. The manner of attachment of this cover assures that very quick and easy inspection of the parts of the apparatus may be made merely by removing this cover while the desk set isin this normal position. It is not necessary to turn the desk set upside down and therefore if this instrument is attached to a supporting surface, for example clamped to the side of a desk or to a wall, it is not essential to unclamp the instrument, from its support but merely necessary to remove by untlons, as shown. Thus need for expert technitary system, the link 66 should extend from tercal knowledge in connecting the parts of the telephone set is avoided. 7

While I have described a particular embodiment of my invention for the purposes of illustration, it should be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in theappended claims.

I claim: i i

1. A telephone subset comprising a terminal block carrying a pluralityof terminal connections, a plurality of individual subset components having terminals projecting from one end thereof, a base plate for supporting said block and said components, means for securing said terminal block to said base plate, means for joining said terminals of said components directly to said terminal connections, and means for securmg said components to said base plate at points spaced from said terminals.

2. A terminal block for a telephone subset comprising a relatively long and narrow mass of insulating material having imbedded therein a plurality of terminal connections, the ends of a plurality of switch springs, and means for interconnecting said terminal connections and said switch springs.

3. A terminal block in accordance with claim 2 wherein is also provided a plurality of connecting prongs for the attachment of external cord connections, means for clamping said cord against said prongs and means for interconnecting said prongs with said terminal connections and said switch springs.

4. A terminal block comprising a plurality of terminal connections, a spring nest, connections between said spring nest and said terminals, said block being of molded material and the ends of said terminal connections and the ends of said spring nest being imbedded therein and interconnected.

5. A telephone subset comprising a supporting structure, a terminal block of molded material separate therefrom, fastened thereto and having therein a plurality of conductors ending, in integral terminal connections, said terminal connections only extending beyond the dimensions of said block, a plurality of active circuit units having terminals projecting therefrom and means for directly interconnecting the terminal connections of said block with the terminal connections of said units whereby the length of exposed circuit conductors is minimized.

6. A telephone subset in accordance with claim 5 wherein each of said units is provided with external terminals which have a given spacing corresponding with the spacing of cooperating terminal connections in said connection block.

7. A telephone subset in accordance with claim 5 wherein a spring nest is molded directly in said terminal block and said subset has a plunger rod arranged to operate said spring nest.

8. A telephone subset in accordance with claim 5 wherein the internal connections in said terminal block are so arranged as to eliminate crossovers inside thereof.

9. A terminal connector block comprising molded insulating material having a plurality of conductors positioned therein, external connections for certain of said conductors, connector prongs for certain of said conductors, screws passing through certain of said conductors and having a. conductor clamp associated therewith. said conductor clamp serving in conjunction with said screws to force a conductor cord against said prongs to form a connection and said conductor clamp likewise serving to form a circuit connection between certain of said conductors.

10. A telephone subset comprising a base plate, a bracket secured to said base plate, a cradle assembly carried by said bracket, a cover fitting around said cradle assembly and secured to said base plate, and a. flexible collar attached to said bracket around said assembly and in contact with said cover whereby a tight closure is formed between said cove and said assembly.

ERNEST S. MCLARN. 

